If one accepts the premise that most physiological functions are controlled by the brain and the medium of that control is electrical signalling as an incident to chemical activity in the brain, then it seems logical to conclude that an absence in the brain of the chemicals required for that activity can result in signal failure and consequent physiological disfunction. It is possible also to conclude that a genetic trait which interferes with such chemical activity can result in signal failure and disfunction. It is also possible to conclude that the presence of a given substance in the brain may interfere chemically with the proper generation of control signals.
Such considerations, the search for an understanding of the mechanism of drug dependence, drunkenness, Alzheimer's disease, schizophrenia and other disorders, some associated with the brain and others apparently not, have lead many researchers to look for a relation between such disorders and availability of chemicals in the brain. The medical literature includes descriptions that comparison of brain tissue of persons who succumbed to a given disease with that of persons who died of unrelated causes suggest a relation between a given chemical and the disease. Thus lack of lithium has been mentioned in connection with schizophrenia and lack of neuropeptides has been mentioned in connection with Alzheimer's disease.
Studies in that area, the chemical treatment of brain cancers, and other studies and procedures are hampered by the difficulty in introducing chemicals into the brain because of what is commonly called the blood-brain barrier. The blood vessels of the brain are formed by cells which are more closely packed than are the vessels elsewhere in the body. That fact and the action of the astrocyte cells account for the fact that many materials are difficult to introduce into the glia of the brain. In some cases the only way that researchers had of getting those materials was to form a hole in the subject's skull and inject the desired material into the brain.
This invention relates to the transportation of material through that blood-brain barrier.